A standard 8-ounce cup of brewed coffee contains roughly 95 to 150 mg of caffeine, while the same size cup of black tea delivers about 40 to 70 mg. That means coffee typically packs two to three times the caffeine of tea, cup for cup. But the actual number in your mug depends heavily on the type of tea or coffee, how you brew it, and how much you use.
Caffeine by Tea Type
All true teas, whether black, green, white, or oolong, come from the same plant. The difference in caffeine comes down to how the leaves are processed and oxidized. Here’s what you can expect per 8-ounce cup brewed at home:
- Black tea: 40 to 70 mg (USDA average around 47 mg)
- Oolong tea: 30 to 55 mg
- Green tea: 20 to 45 mg (USDA average around 28 mg)
- White tea: 15 to 40 mg
- Matcha: 60 to 70 mg per standard 2-gram serving
- Decaf tea: 2 to 5 mg
Matcha stands out because you’re consuming the whole ground leaf rather than steeping and discarding it. That pushes its caffeine closer to coffee territory. Herbal “teas” like chamomile, rooibos, and peppermint contain zero caffeine since they aren’t made from the tea plant at all. The exceptions are yerba mate (30 to 85 mg per cup) and guayusa (40 to 70 mg), which come from naturally caffeinated plants.
Caffeine by Coffee Type
The range for coffee is wider than most people realize. A single shot of espresso (about 2 ounces) contains roughly 108 mg of caffeine, which sounds like a lot until you consider that a full 8-ounce cup of drip coffee lands between 107 and 151 mg. Espresso is more concentrated per ounce, but a typical serving is much smaller, so you often end up with similar or even less total caffeine than a regular cup.
Instant coffee is the lightest option in the coffee family, averaging about 57 mg per 6-ounce cup. If you’re trying to cut back on caffeine but still want the coffee ritual, instant is a straightforward swap that roughly halves your intake compared to drip.
Roast level makes less difference than you might think. Light roasts and dark roasts contain very similar amounts of caffeine when measured by weight. Dark roasting causes beans to expand and lose some water, so if you scoop by volume (tablespoons), a scoop of light roast will have slightly more caffeine because the beans are denser and you’re getting more actual coffee per scoop. But the difference is small, roughly 60 mg versus 51 mg in one comparison, and it varies between batches. Choose your roast for flavor, not caffeine.
Why Tea Feels Different Than Coffee
Many tea drinkers describe a calmer, more sustained alertness compared to the sharper buzz they get from coffee. The likely reason is an amino acid called L-theanine, which is found naturally in tea leaves but not in coffee beans. L-theanine doesn’t slow down how fast your body absorbs caffeine. Salivary caffeine levels are essentially the same whether caffeine is consumed alone or alongside L-theanine. What it does change is how caffeine affects blood flow in the brain.
In a controlled study published in Psychopharmacology, caffeine alone constricted blood flow to the brain in a predictable pattern. When L-theanine was present alongside the caffeine, that constriction was significantly blunted. The combination seems to smooth out some of caffeine’s more aggressive effects on the brain’s vascular system, which may explain why a cup of tea feels gentler even though it still contains a meaningful dose of caffeine.
Interestingly, the same study found that caffeine alone improved reaction time, mental performance, and mood ratings, but those improvements disappeared when L-theanine was added. So the tradeoff with tea may be a smoother, less jittery experience at the cost of some of the acute sharpness coffee drinkers rely on.
How Brewing Changes the Numbers
The ranges listed above assume typical home brewing, but small changes in your process can push caffeine up or down significantly. Two factors matter most: water temperature and steeping time.
For coffee, caffeine extraction peaks at water temperatures between 90°C and 100°C (194°F to 212°F) with about 15 minutes of contact time. Most drip machines hit this range automatically. Robusta beans also contain substantially more caffeine than Arabica beans at any temperature, so the species of bean in your bag matters as much as how you brew it. Most specialty coffee is Arabica; cheaper blends and instant coffee often contain Robusta.
Tea behaves differently. Research on caffeine extraction from tea leaves found that the optimal temperature for releasing caffeine, beneficial catechins, and L-theanine is between 45°C and 75°C (113°F to 167°F). At 90°C, the chemical content dropped considerably. This means brewing tea with boiling water, as many people do, can actually reduce the caffeine and beneficial compounds you extract. Steeping at a lower temperature for a longer time tends to yield more of both.
Steep time is the easiest variable to control. A black tea steeped for one minute might deliver 25 mg of caffeine, while the same tea bag left in for five minutes could approach 70 mg. If you want more caffeine from tea without switching to coffee, let it brew longer.
Fitting It Into Your Day
The FDA considers up to 400 mg of caffeine per day safe for most healthy adults. That translates to roughly two to three 12-ounce cups of coffee, or about eight to ten cups of black tea. Most tea drinkers never come close to that ceiling, even with several cups a day. Coffee drinkers can hit it more easily, especially with large servings or double espresso drinks.
For context, toxic effects like seizures can occur with rapid consumption of around 1,200 mg, which is nearly impossible to reach through brewed beverages but alarmingly easy with pure caffeine powder (less than half a teaspoon). This is why concentrated caffeine supplements carry real risk while normal tea and coffee consumption does not.
If you’re switching from coffee to tea to reduce your caffeine intake, black tea will roughly cut your per-cup dose in half. Going from black tea to green tea halves it again. And if you want the ritual without the stimulant, herbal teas give you a warm cup with zero caffeine, while decaf versions of black or green tea keep it under 5 mg.